Packaging container and method for manufacturing the same

Abstract

The present invention provides a packaging container that has excellent ease of opening and sealing properties, with an opening hole formed upon opening. [Solution] A packaging container comprising a container body having an opening and a flange, and a lid material that seals to the flange and closes the opening, wherein the lid material comprises a base layer, an intermediate layer, an extruded resin layer laminated on the intermediate layer in a peelable manner by extrusion, and a sealant layer, the thickness of the sealant layer being 10 μm or more and 70 μm or less, no adhesive layer included between the sealant layer and the intermediate layer, a half-cut is formed that surrounds a predetermined area of ​​the lid material and extends from the sealant layer to partway up the intermediate layer, and the sealed area of ​​the lid material that is sealed to the flange is provided with an embossed portion composed of a plurality of recesses, the width of the flat surface formed at the bottom of the recess is 0.1 mm or more and 0.6 mm or less, the depth is 0.15 mm or more and 0.45 mm or less, and the pitch between adjacent recesses is 0.6 mm or more and 1.5 mm or less.

Description

TECHNICAL FIELD

[0001] The present invention relates to a packaging container configured by sealing a lid material to a container body, and a method for manufacturing the same. BACKGROUND ART

[0002] Among packaging containers for beverages and the like, those in which a film lid material is sealed to the opening of a cup-shaped container body are known. Such packaging containers can be used for drinking by inserting a straw through the lid material, but in recent years, from the perspective of reducing environmental load, the need for packaging containers that allow direct drinking without using a straw has been increasing. Accordingly, packaging containers in which an opening serving as a drinking spout is formed in a part of the lid material by partially peeling off the film lid material have been studied.

[0003] Such a lid material that forms an opening when opened has a multilayer structure in which one or more layers including a sealant layer are laminated on a base material layer and an intermediate layer, and by providing an easily peelable portion at the interlayer between the intermediate layer and the sealant layer, the base material layer and the intermediate layer are configured to be peelable from the lid material. The lid material is provided with a half-cut line, which is provided near the opening of the container body and serves as a trigger for delaminating the lid material, and a half-cut line formed so as to surround a predetermined region overlapping with the opening for forming a drinking spout, and each half-cut line is formed from the sealant layer to the middle of the intermediate layer. The delamination between the intermediate layer and the sealant layer starts from the half-cut line that triggers delamination when the lid material is peeled from the container body, but peeling does not occur within the region of the half-cut line for forming the drinking spout, and all layers of the base material layer, the intermediate layer and the sealant layer are removed, so that an opening serving as a drinking spout can be formed (Patent Documents 1 to 3). PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] PATENT DOCUMENT 1 Japanese Unexamined Patent Publication No. 2015-758 PATENT DOCUMENT 2 Japanese Unexamined Patent Publication No. 2021-59373 [Patent Document 3] Patent No. 4572660 [Overview of the project] [Problems that the invention aims to solve]

[0005] The lid material is welded to the container body after a half-cut line is formed. At this time, it is necessary to weld the lid material so that the half-cut line, which triggers delamination, is located around the opening of the container body. However, with general welding using a filling machine, it was difficult to keep the positional misalignment within an acceptable range. If the positional misalignment exceeds the acceptable range, the ease of opening deteriorates, and even if the half-cut line that triggers delamination is formed, delamination between the intermediate layer and the sealant layer may not occur, and a drinking spout may not be formed after opening. Furthermore, it is also important not to impair the airtightness of such beverage packaging containers.

[0006] This invention has been made in view of the above problems, and aims to provide a packaging container that has an opening hole formed when opened, and is excellent in terms of ease of opening and sealing. [Means for solving the problem]

[0007] One aspect of the present invention for solving the above problems is a packaging container comprising a container body having an opening and a flange, and a lid material that seals to the flange and closes the opening, wherein the lid material comprises a base layer, an intermediate layer laminated on one side of the base layer, an extruded resin layer that is peelably laminated on the intermediate layer by extrusion, and a sealant layer laminated on the extruded resin layer, the thickness of the sealant layer being 10 μm or more and 70 μm or less, no adhesive layer included between the sealant layer and the intermediate layer, a half-cut is formed that surrounds a predetermined area of ​​the lid material and extends from the sealant layer to partway up the intermediate layer, and the sealing area of ​​the lid material that is sealed to the flange is provided with an embossed portion composed of a plurality of recesses, the width of the flat surface formed at the bottom of the recess is 0.1 mm or more and 0.6 mm or less, the depth is 0.15 mm or more and 0.45 mm or less, and the pitch between adjacent recesses is 0.6 mm or more and 1.5 mm or less.

[0008] Another aspect of the present invention is a method for manufacturing a packaging container, in which the flange of the container body and the lid material are welded together using a hot plate that has knurling, with a flat surface formed at the top having a width of 0.1 mm or more and a depth of 0.15 mm or more and a pitch between the protrusions of 0.6 mm or more and a pitch between the protrusions of 1.5 mm or less. [Effects of the Invention]

[0009] According to the present invention, an opening is formed when the container is opened, providing a packaging container with excellent ease of opening and sealing properties. [Brief explanation of the drawing]

[0010] [Figure 1] Schematic plan view of a packaging container according to an embodiment. [Figure 2] Schematic side view of a packaging container according to an embodiment. [Figure 3] Schematic plan view of the packaging container after opening. [Figure 4] Partial cross-sectional view along line A-A' in Figure 3 [Figure 5] Cross-sectional view of the lid material around the half-cut area, showing its condition before opening. [Figure 6] Cross-sectional view of the embossed portion of the lid member in the state before opening [Figure 7A] Schematic plan view of knurling formed on a hot plate [Figure 7B] Cross-sectional view taken along line B-B' of Figure 7A [Figure 8A] Schematic partial cross-sectional view showing the state of the packaging container before opening [Figure 8B] Schematic partial cross-sectional view showing the state of the packaging container after opening [Figure 9] Cross-sectional view of a lid member according to a reference example [Modes for Carrying Out the Invention]

[0011] [Embodiment] Figure 1 is a schematic plan view of the packaging container according to the embodiment, and Figure 2 is a schematic side view of the packaging container according to the embodiment. Figure 3 is a schematic plan view of the packaging container showing the state after opening, and Figure 4 is a partial cross-sectional view taken along line A-A' of Figure 3. Figure 5 is a cross-sectional view of the periphery of the half-cut of the lid member in the state before opening. Figure 6 is a cross-sectional view of the embossed portion of the lid member in the state before opening.

[0012] [Configuration] (Packaging container) The packaging container 100 includes a lid member 1 and a container body 2. The packaging container 100 is, for example, a cup-type beverage container that allows direct drinking without using a straw. When the packaging container 100 is opened, the lid member 1 can be partially separated from the container body 2, and an opening hole 5 serving as a drinking spout is formed in a part of the lid member 1 remaining on the container body 2 (Figures 3 and 4).

[0013] (Container body) The container body 2 has an opening 21, and a flange 22 is provided on the peripheral edge of the opening 21. Although the opening 21 of the container body 2 is illustrated as circular in Figure 1, it may have other shapes.

[0014] (Lid member) The lid member 1 includes a closing portion 3 and a pull tab 4 provided on a part of the outer peripheral edge of the closing portion 3, and is formed of a film having a multilayer structure. Of the closing portion 3, an annular region along the outer peripheral edge is sealed with the flange 22 of the container body 2, and closes the opening 21 of the container body 2. The pull tab 4 is a member to be gripped when peeling the lid member 1 from the packaging container 100, and is provided on a part of the outer peripheral edge of the closing portion 3. The shape of the pull tab 4 is not particularly limited as long as it is a shape that is easy to grip at the time of opening.

[0015] As shown in FIG. 5, the lid member 1 is constituted by a film having, in order from the outside, a base material layer 11, an intermediate layer 12 laminated on one surface of the base material layer 11, an extruded resin layer 13 releasably laminated on the intermediate layer 12, and a sealant layer 14 laminated on the extruded resin layer 13. As shown in FIGS. 1 and 5, the lid member 1 is provided with a half cut 6 that extends from the sealant layer 14 to the middle of the intermediate layer 12. Further, as shown in FIGS. 1 and 6, the lid member 1 includes an embossed portion 7 in which an embossing process constituted by a plurality of recesses is applied to a seal region sealed with the flange 22 of the lid member 1. The base material layer 11 and the intermediate layer 12 may be bonded via an adhesive layer 15, but no adhesive or anchor coating agent is contained between the sealant layer 14 and the intermediate layer 12. When an adhesive or an anchor coating agent is contained between the sealant layer 14 and the intermediate layer 12, the half cut 6 traverses the same, so that the adhesive is exposed to the surface and may come into contact with the content, which is not preferable.

[0016] The base material layer 11 is a base material of the lid member 1. As the base material layer 11, for example, polyethylene terephthalate (PET) can be used, and the thickness can be 9 μm to 50 μm. Further, other layers such as a printed layer may be appropriately laminated on the base material layer 11.

[0017] The intermediate layer 12 is laminated on one surface of the base material layer 11 via the adhesive layer 15. Since the half cut 6 is formed so as not to penetrate the intermediate layer 12, the intermediate layer 12 is peeled off from the container body 2 side together with the base material layer 11 when the lid member 1 is opened, and is separated from the lid member 1.

[0018] The Young's modulus of the intermediate layer 12 is preferably 1.5 GPa or higher. If the Young's modulus is less than 1.5 GPa, due to the flexibility of the intermediate layer 12, the layers remaining on the container body 2 side (extruded resin layer 13 and sealant layer 14) may stretch along the half-cut 6 when opened, and the opening hole 5 may not be formed properly. Also, if the Young's modulus is too high, the rigidity of the intermediate layer 12 will increase, which may make it difficult to break the half-cut 6 when opening. For this reason, for example, the Young's modulus is preferably 5.0 GPa or lower. As the intermediate layer 12, for example, films such as stretched polypropylene (OPP), heat-sealed stretched polypropylene (HSOPP), stretched nylon (ONY), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and heat-sealed polyethylene terephthalate (HSPET) can be used.

[0019] However, even if the Young's modulus of the intermediate layer 12 is less than 1.5 GPa, there are methods to suppress the elongation of the extruded resin layer 13 and the sealant layer 14. For example, as shown in the reference example in Figure 9, by providing a stretched PET layer 17 on the inner side of the intermediate layer 12, the suitability for half-cut processing is improved, and the opening hole 5 can be formed normally. However, when providing a stretched PET layer 17, it is necessary to use an anchor coating agent 18 or adhesive layer 19 as appropriate to improve the adhesion between the stretched PET layer 17 and the extruded resin layer 13, and between the stretched PET layer 17 and the sealant layer 14. Since a half-cut 6 is formed on the inner side of the intermediate layer 12, the adhesive is exposed from the cross-section of the half-cut 6, making it unsuitable for food applications. Therefore, in this embodiment, by setting the Young's modulus of the intermediate layer 12 to 1.5 GPa or higher, the opening hole 5 can be formed normally without providing a stretched PET layer 17 and an adhesive layer on the inner side of the intermediate layer 12.

[0020] The extruded resin layer 13 is laminated on the intermediate layer 12 by extrusion in a peelable manner without an adhesive layer, and after the base layer 11 and the intermediate layer 12 are peeled off, it remains in the opening 21 of the container body 2 together with the sealant layer 14 to form the opening hole 5. For example, polyethylene (PE) can be used as the extruded resin layer 13, and its thickness can be 10 μm to 30 μm. The extruded resin layer 13 can be peeled off from the intermediate layer 12, and in this case, the interlayer strength between the extruded resin layer 13 and the intermediate layer 12 is preferably 0.1 N / 15 mm or more and 1 N / 15 mm or less, and more preferably 0.1 N / 15 mm or more and 0.8 N / 15 mm or less. If the interlayer strength between the extruded resin layer 13 and the intermediate layer 12 is less than 0.1 N / 15 mm, unintended delamination may occur during the transportation of the packaging container 100. Furthermore, if the interlayer strength between the extruded resin layer 13 and the intermediate layer 12 exceeds 1 N / 15 mm, the force required to open the packaging container 100 will increase, making it difficult to open. The extruded resin layer 13 can be formed by extrusion lamination, and the interlayer strength can be adjusted by slowing down the lamination speed to increase it and by speeding up the lamination speed to decrease it.

[0021] The sealant layer 14 is welded to the flange 22 of the container body 2 and remains with the extruded resin layer 13 after the base layer 11 and intermediate layer 12 are peeled off, forming the opening 5. The material of the sealant layer 14 must be a material that can be welded to the flange 22, for example, linear low-density polyethylene (LLDPE) or unoriented polypropylene (CPP) can be used. The thickness of the sealant layer 14 is 10 μm or more and 70 μm or less, and more preferably 20 μm or more and 50 μm or less. If the thickness of the sealant layer 14 is less than 10 μm, the welding strength between the lid material 1 and the flange 22 will be insufficient, and the contents may leak. If it exceeds 70 μm, the sealant layer 14 will not be thin enough during welding, so it may not be possible to induce peeling between the intermediate layer 12 and the extruded resin layer 13 starting from the embossed portion 7 of the lid material 1, and the ease of opening may be poor (details will be described later).

[0022] (Embossed area) The embossed portion 7 is a part of the lid material 1 that has been embossed with multiple recesses 8, and is applied to the region X of the lid material 1 that overlaps with the flange 22 in a plan view (the shaded region in Figure 1). The embossed portion 7 is obtained by pressing a knurled hot plate, as shown in Figures 7A and 7B, against the base material layer 11 side of the lid material 1 to weld the lid material 1 and the flange 22. The embossed portion 7 only needs to be formed along the outer circumference of the flange 22 facing the pull tab 4, and may be formed in a region wider than the region that overlaps with the entire circumference of the flange 22, as shown in Figure 1.

[0023] The recess 8 is formed when the knurled portion 8' of the hot plate presses against the lid material 1, so the pressure during welding is stronger in the recess 8 (more specifically, the flat surface 9, which is the most compressed part of the recess 8). As a result, the sealant layer 14 in the recess 8 becomes thinner than in other welded parts of the lid material 1, and the welding strength is also higher. Furthermore, as shown in Figure 6, in the part of the lid material 1 pressed by the portion 8', the adhesion at the easily peelable area (between the intermediate layer 12 and the extruded resin layer 13) becomes distorted due to the thinning of the sealant layer 14, and the peel strength between the intermediate layer 12 and the extruded resin layer 13 is weakened.

[0024] Thus, in the area of ​​the lid material 1 where the recess 8 is formed, the welding strength between the sealant layer 14 and the flange 22 is higher than in other areas, and the peel strength between the intermediate layer 12 and the extruded resin layer 13 is weaker. Therefore, the embossed portion 7 functions as a trigger for separation of the base layer 11 and the intermediate layer 12 from the lid material 1 when the lid material 1 is peeled off starting from the pull tab 4, causing delamination between the intermediate layer 12 and the extruded resin layer 13.

[0025] Each of the multiple recesses 8 constituting the embossed section 7 has a flat surface 9 at its bottom that is substantially parallel to the flange 22, and the width W of the flat surface 9 is 0.1 mm or more and 0.6 mm or less. The width W of the flat surface 9 is the minimum width in the row and column directions when the recesses are arranged in a matrix. If the width W of the flat surface 9 is less than 0.1 mm, the welding strength per unit area between the sealant layer 14 and the flange 22 will be insufficient, and there is a risk that delamination between the intermediate layer 12 and the extruded resin layer 13 will not occur, and the tip of the knurled protrusion 8', which will be described later, may become sharp and penetrate the lid material 1. If it exceeds 0.6 mm, the pressure applied to the lid material 1 from the knurled protrusion 8' will be dispersed, resulting in insufficient welding strength between the sealant layer 14 and the flange 22, and there is a risk that the sealant layer 14 in the recess 8 will not become sufficiently thin, and delamination between the intermediate layer 12 and the extruded resin layer 13 may not occur.

[0026] Furthermore, the pitch P between adjacent recesses 8 in the direction of the width W of the flat surface 9 shall be 0.6 mm or more and 1.5 mm or less. If the pitch P is less than 0.6 mm, it becomes difficult to process the knurling to form the embossed surface. If it exceeds 1.5 mm, the spacing between adjacent recesses 8 is too wide, and there is a risk of liquid leakage where the contents leak out. Here, the depth D of the recesses 8 shall be 0.15 mm or more and 0.45 mm or less. If the depth D of the recesses 8 is less than 0.15 mm, the thickness of the sealant layer 14 in the recesses 8 cannot be made sufficiently thinner than other parts, and there is a risk that delamination between the intermediate layer 12 and the extruded resin layer 13 will not occur. If it exceeds 0.45 mm, it becomes difficult to keep the pitch P between adjacent recesses 8 to 1.5 mm or less in terms of knurling processing. Furthermore, from the viewpoint of sealing performance, it is more preferable that the pitch P between adjacent recesses 8 be 1.0 mm or less.

[0027] Figure 7A shows a schematic plan view of the knurling formed on the hot plate, and Figure 7B shows a cross-sectional view along the line B-B' in Figure 7A. Multiple protrusions 8' are formed on the knurling of the hot plate, and each of the multiple protrusions 8' corresponds to the shape of each of the recesses 8 of the embossed section 7. The top of each protrusion 8' (corresponding to the bottom of the recess 8) also has a flat surface 9', similar to the multiple recesses 8. The width W' of each flat surface 9' of the multiple protrusions 8', the pitch P' between adjacent protrusions 8', and the depth D' should all be set to be approximately equal to the shape of the recess 8 of the target embossed section 7. Specifically, the width W' of the flat surface 9' should be 0.1 mm or more and 0.6 mm or less, the pitch P' between adjacent protrusions 8' should be 0.6 mm or more and 1.5 mm or less, and the depth D' should be 0.15 mm or more and 0.45 mm or less. Furthermore, the angle α formed by the two slopes separating adjacent recesses 8 is set to an angle that easily deforms the laminate constituting the lid material 1 during welding, and can be, for example, 45° to 150°.

[0028] (Half cut) The half-cut 6 is an annular line formed by a cut that extends from the sealant layer 14 to partway through the intermediate layer 12 (Figure 5). Inside the half-cut 6, a drinking spout (opening 5) is formed when all the laminate is removed after opening. Therefore, the half-cut 6 is formed in the area that is inside the flange 22 of the lid material 1 when the lid material 1 is sealed to the container body 2. The configuration of the half-cut 6 is not particularly limited, but for example, it may be composed of a straight cut, or it may be composed of dot-shaped cuts arranged in a line.

[0029] When the lid material 1 is peeled away from the container body 2, the extruded resin layer 13 and sealant layer 14 in the area inside the half-cut 6 of the lid material 1 are separated from the lid material 1 together with the base layer 11, but the extruded resin layer 13 and sealant layer 14 in the area outside the half-cut 6 remain on the container body 2 side. As a result, an opening hole 5 along the outer diameter of the half-cut 6 is formed in the lid material 1 (extruded resin layer 13 and sealant layer 14). The shape of the half-cut 6 is formed to surround a predetermined area of ​​the lid material 1 and is not particularly limited as long as it is a shape suitable for a drinking spout, but for example it can be circular, elliptical, teardrop-shaped, etc.

[0030] [Effect] Figure 8A is a schematic partial cross-sectional view showing the packaging container before opening, and Figure 8B is a schematic partial cross-sectional view showing the packaging container after opening.

[0031] To open the packaging container 100 according to this embodiment, the pull tab 4 should be pulled in the same way as opening a general packaging container, in the direction that separates the lid material 1 from the container body 2. Then, delamination occurs between the intermediate layer 12 and the extruded resin layer 13 of the lid material 1, triggered by the embossed portion 7 formed at the welding location between the lid material 1 and the flange 22. At this time, in the recess 8 (flat surface 9), the welding strength between the sealant layer 14 and the flange 22 is higher than in other welded areas of the lid material 1. Also, in the recess 8 (flat surface 9), the adhesion between the intermediate layer 12 and the extruded resin layer 13 is distorted due to the thinning of the sealant layer 14 during welding, resulting in weaker peel strength. In other words, in the area of ​​the lid material 1 where the recess 8 is formed, the welding strength between the sealant layer 14 and the flange 22 is higher than in other areas, and the peel strength between the intermediate layer 12 and the extruded resin layer 13 is weaker. Therefore, near the edge of the bottom surface of the recess 8, fracture (edge ​​breakage) occurs in the sealant layer 14 and the extruded resin layer 13. As a result, the base material layer 11 and the extruded resin layer 13 separate, starting from the embossed portion 7 (Figure 8B).

[0032] Furthermore, if the sealant layer 14 is thick, the thickness of the sealant layer 14 in the recess 8 will not be sufficiently thinner than in other areas during welding. This may prevent the delamination of the intermediate layer 12 and the extruded resin layer 13 starting from the embossed portion 7, potentially resulting in poor openability. Therefore, the upper limit of the sealant layer 14 thickness should be 70 μm or less, and more preferably 50 μm or less.

[0033] When the pull tab 4 is pulled further, the intermediate layer 12 and the extruded resin layer 13 begin to separate. However, because an annular half-cut 6 is formed in the direction of separation (from the pull tab 4 toward the center of the closed portion 3), interlayer delamination does not occur in the region inside the half-cut 6. As a result, the extruded resin layer 13 and the sealant layer 14 in the region inside the half-cut 6 are separated from the lid material 1 together with the base layer 11 and the intermediate layer 12, and an opening 5 can be formed in the lid material 1 (Figure 8B).

[0034] [effect] As described above, the lid material 1 according to this embodiment has an embossed area X that is sealed with the flange 22, and the width W of the flat surface 9 of the recess 8 in the embossed area 7 is 0.1 mm or more and 0.6 mm or less. This makes it possible to cause delamination between the intermediate layer 12 and the extruded resin layer 13, starting from the embossed area 7.

[0035] Furthermore, the pitch P between adjacent recesses 8 is 0.6 mm or more. This allows for more reliable knurling to form the embossed pattern.

[0036] Furthermore, the pitch P between adjacent recesses 8 is 1.5 mm or less. This prevents liquid leakage from occurring due to excessively wide spacing between adjacent recesses 8.

[0037] Furthermore, the depth D of the recess 8 is 0.15 mm or more. This allows the thickness of the sealant layer 14 to be sufficiently thin compared to other parts, and enables more reliable separation of the intermediate layer 12 and the extruded resin layer 13.

[0038] Furthermore, the depth D of the recess 8 is 0.45 mm or less. This makes it possible to more reliably keep the pitch between adjacent recesses 8 to 1.5 mm or less.

[0039] Furthermore, the thickness of the sealant layer 14 is between 10 μm and 70 μm. This ensures sufficient welding strength between the lid material 1 and the flange 22, while also making the thickness of the sealant layer 14 in the recess 8 (flat surface 9) sufficiently thin to induce edge breakage and cause delamination between the intermediate layer 12 and the extruded resin layer 13.

[0040] Furthermore, there is no adhesive layer between the sealant layer 14 and the intermediate layer 12. This prevents the adhesive from seeping into the contents from the half-cut cross-section 6.

[0041] Furthermore, the Young's modulus of the intermediate layer 12 is 1.5 GPa or higher. This suppresses the elongation of the extruded resin layer 13 and the sealant layer 14 along the half-cut 6, allowing the opening 5 to be formed normally.

[0042] Furthermore, the embossed portion 7, which triggers the delamination between the intermediate layer 12 and the extruded resin layer 13, is formed simultaneously with the welding of the lid material 1 to the container body 2. Therefore, positional misalignment is less likely to occur compared to the conventional method, where a half-cut line that triggers delamination is formed on the lid material 1 before welding the lid material 1 to the container body 2, and the delamination between the intermediate layer 12 and the extruded resin layer 13 can be performed more reliably. [Examples]

[0043] Laminates with layer configurations A to H were fabricated. The configuration of each layer is as follows. Note that the areas indicated by " / / " are areas where the lid material has peeled off. Layer composition A: PET12 / adhesive layer / HSOPP40 / / extruded PE15 / LLDPE25 Layer configuration B: PET12 / adhesive layer / PET25 / / extruded PE15 / LLDPE25 Layer composition C: PET12 / adhesive layer / PBT25 / / extruded PE15 / LLDPE25 Layer composition D: PET12 / adhesive layer / ONY25 / / extruded PE15 / LLDPE25 Layer composition E: PET12 / adhesive layer / OPP40 / extruded PE15 / LLDPE25 Layer composition F: PET12 / adhesive layer / HSOPP40 / / extruded PE15 / LLDPE70 Layer composition G: PET12 / adhesive layer / HSOPP40 / / extruded PE15 / LLDPE80 Layer composition H: PET12 / adhesive layer / CPP50 / / extruded PE15 / anchor coating agent / PET12 / adhesive layer / LLDPE25

[0044] (Example 1) Using a laminate having layer configuration A, a lid material was fabricated with a half-cut extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (HSOPP layer).

[0045] <Evaluation of ease of opening> The fabricated lid material was welded to the flange of a container body containing 100 ml of water using a knurled hot plate at 190°C, 1.25 s, and 0.4 MPa to obtain a packaging container for openability evaluation. At this time, the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, and the width W of the flat surface of the recessed parts of the embossed parts formed on the lid material 1, the pitch P between adjacent recessed parts, and the depth D of the recessed parts were the same.

[0046] The packaging containers prepared for openability evaluation were opened by each of the 20 monitors while holding the pull tab on the lid. A score of ○ was given if 18 or more out of 20 people were able to successfully separate the intermediate layer from the extruded resin layer and form a drinking spout (opening), and a score of × was given if 17 or fewer people were able to do so.

[0047] <Sealability Evaluation> The fabricated lid material was welded to the flange of the container body using a knurled hot plate to obtain a packaging container for evaluating airtightness. At this time, the welding conditions and the shape of the knurling were the same as those used when the packaging container for evaluating openability was fabricated.

[0048] The bottom of the prepared packaging container for evaluating airtightness was cut off, and the permeate solution was poured in. The presence or absence of leakage between the lid and the container body was checked. At this time, a ◎ was used to indicate that no permeation of the permeate solution was observed, a ○ was used to indicate that some permeation was observed but no leakage occurred, and a × was used if leakage occurred.

[0049] (Examples 2-6) Except for the fact that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealability evaluations were performed in the same manner as in Example 1.

[0050] (Examples 7-12) Except for the fact that a half-cut was formed using a laminate having layer configuration B, extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (PET layer), and that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealing performance evaluations were performed in the same manner as in Example 1.

[0051] (Example 13) Except for the fact that a half-cut was formed using a laminate having layer configuration C, extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (PBT layer), and that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealing performance evaluations were performed in the same manner as in Example 1.

[0052] (Example 14) Except for the fact that a half-cut was formed using a laminate having layer configuration D, extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (ONY layer), and that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealing performance evaluations were performed in the same manner as in Example 1.

[0053] (Example 15) Except for the fact that a half-cut was formed using a laminate having layer configuration E, extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (OPP layer), and that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealing performance evaluations were performed in the same manner as in Example 1.

[0054] (Example 16) Except for the fact that a half-cut was formed using a laminate having layer configuration F, extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (HSOPP layer), and that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealing performance evaluations were performed in the same manner as in Example 1.

[0055] (Comparative Example 1) Except for the fact that a half-cut was formed using a laminate having layer configuration G, extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (HSOPP layer), and that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealing performance evaluations were performed in the same manner as in Example 1.

[0056] (Comparative Example 2) Except for the fact that a half-cut was formed using a laminate having layer structure H, extending from the sealant layer (LLDPE layer) to partway through the intermediate layer (CPP layer), and that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealing performance evaluations were performed in the same manner as in Example 1.

[0057] (Comparative Example 3) Except for the fact that the width W' of the flat surface of the knurled protrusions, the pitch P' between adjacent protrusions, and the depth D' of the protrusions were as shown in Table 1, the openability and sealability evaluations were performed in the same manner as in Example 1.

[0058] (Comparative Example 4) Except for welding the lid material using a hot plate without knurling, i.e., not embossing the lid material, the opening ease and sealing ease evaluations were performed in the same manner as in Example 1.

[0059] <Evaluation of suitability for food products> The lid materials for Examples 1-16 and Comparative Examples 1-4 were evaluated according to the following criteria to determine whether they could be used for food applications. ○: No adhesive or anchor coating agent is exposed from the cross-section of the half-cut. ×: Adhesive or anchor coating is exposed from the half-cut surface.

[0060] The layer structure of the lid material for Examples 1-16 and Comparative Examples 1-4, the thickness of the sealant layer, the shape of the recessed parts of the embossed section (shape of the raised parts of the knurling), and the evaluation results of the openability evaluation, airtightness evaluation, food suitability evaluation, and overall evaluation are shown below. The overall evaluation was performed according to the following criteria. ◎: If there are no ×s in the openability evaluation, airtightness evaluation, or food suitability evaluation, and the airtightness evaluation is ◎. ○: If there are no ×s in the openability evaluation, airtightness evaluation, or food suitability evaluation, and the airtightness evaluation is ○. ×: If there is an × in any of the following evaluations: ease of opening, airtightness, or suitability for food products.

[0061] [Table 1]

[0062] In all of the packaging containers in Examples 1 to 16, the sealant layer thickness was 70 μm or less, the width W of the flat surface of the recess in the embossed area was 0.1 mm to 0.6 mm, and the depth D of the recess was 0.15 mm or more. As a result, the thickness of the sealant layer in the recess 8 (flat surface 9) was sufficiently thin, which induced edge breakage in the embossed area. This allowed for normal delamination between the intermediate layer and the extruded resin layer, and the drinking spout (opening) could be formed.

[0063] Furthermore, in all of the packaging containers in Examples 1 to 16, the sealant layer thickness was 10 μm or more, so the welding strength of the lid material was sufficient, and the pitch P between adjacent recesses 8 was 1.5 mm or less. As a result, no liquid leakage occurred.

[0064] Furthermore, in all of the packaging containers of Examples 1 to 16, the adhesive and anchor coating agent were not exposed from the half-cut cross-section, making them suitable for use as food packaging containers.

[0065] In Comparative Example 1, the sealant layer of the packaging container was thicker than 70 μm, so the sealant layer did not become sufficiently thin during welding. As a result, delamination between the intermediate layer and the extruded resin layer, starting from the embossed area, could not be induced, resulting in poor openability.

[0066] The packaging container in Comparative Example 2 had adhesive and anchor coating exposed from the half-cut cross-section, making it unsuitable for use as a food packaging container. Furthermore, despite the sealant layer thickness being 70 μm or less, the width W of the flat surface of the recess in the embossed area being 0.1 mm to 0.6 mm, and the recess depth D being 0.15 mm or more, the openability evaluation result was "fail". This is thought to be because a PET layer with a higher melting point than the sealant layer was provided on the inner layer side of the intermediate layer (CPP layer in the H configuration), making it impossible to sufficiently reduce the thickness of the recess 8 (flat surface 9).

[0067] In Comparative Example 3, the depth D of the recess 8 in the packaging container exceeded 0.45 mm, and therefore the pitch P between adjacent recesses 8 also exceeded 1.5 mm. As a result of the pitch P exceeding 1.5 mm, liquid leakage occurred.

[0068] In Comparative Example 4, the packaging container lacked embossing on the lid material, which prevented the separation of the intermediate layer and the extruded resin layer, resulting in poor opening.

[0069] Furthermore, in the packaging containers of Examples 1-5, 7-11, 13-16, and Comparative Examples 1-2, no penetration of the liquid was observed during the airtightness evaluation, indicating excellent airtightness. This is presumed to be because the pitch P between the recesses 8 was 1.0 mm or less. [Industrial applicability]

[0070] The present invention can be used as a packaging container in which a lid material is sealed to the container body and an opening is formed when opened, or as a method for manufacturing said packaging container. [Explanation of Symbols]

[0071] 1: Lid material 2: Container body 6: Half cut 7: Embossed section 8: Recess 8': Convex part 9: Flat surface 9': Flat surface 11: Base material layer 12: Middle Class 13: Extruded resin layer 14: Sealant layer 15: Adhesive layer 19: Adhesive layer 21 :Aperture 22: Flange 100: Packaging container D: Depth D': Depth P: Pitch P': Pitch W: Width W':Width X: Area where embossing will be applied.

Claims

1. A packaging container comprising a container body having an opening and a flange, and a lid material that seals to the flange and closes the opening, The aforementioned lid material is A base layer and An intermediate layer laminated on one side of the base material layer, An extruded resin layer is laminated on the intermediate layer in a manner that allows it to be peeled off by extrusion, The extruded resin layer comprises a sealant layer laminated on the aforementioned extruded resin layer, The thickness of the sealant layer is 10 μm or more and 70 μm or less. The sealant layer and the intermediate layer do not contain an adhesive layer. A half-cut is formed in the lid material, extending from the sealant layer to partway up the intermediate layer, so as to surround a predetermined area of ​​the lid material. The sealing region of the lid material that is sealed with the flange is provided with an embossed portion that is embossed with a plurality of recesses, The width of the flat surface formed at the bottom of the recess is 0.1 mm or more and 0.6 mm or less, and the depth is 0.15 mm or more and 0.45 mm or less. A packaging container in which the pitch between adjacent recesses is 0.6 mm or more and 1.5 mm or less.

2. The packaging container according to claim 1, wherein the pitch is greater than 0.6 mm and less than 1.0 mm.

3. The packaging container according to claim 1, wherein the thickness of the sealant layer is 20 μm or more and 50 μm or less.

4. The packaging container according to claim 1, wherein the Young's modulus of the intermediate layer is 1.5 GPa or more.

5. A method for manufacturing a packaging container according to claims 1 to 4, A method for manufacturing a packaging container, comprising welding the flange of the container body and the lid material using a hot plate that has knurling, with a flat surface formed on its top having a width of 0.1 mm or more and a depth of 0.15 mm or more and a pitch between the protrusions of 0.6 mm or more and a pitch between the protrusions of 1.5 mm or less.

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